1. Field of the Invention
The present invention relates to a hetero-junction semiconductor device and a method of manufacturing a hetero-junction semiconductor device.
2. Description of Related Art
Disclosed is a nitride semiconductor device which is a hetero-junction semiconductor element device in which a channel layer formed of gallium nitride (GaN) and a barrier layer formed of aluminum gallium nitride (AlGaN) are joined to each other. In this nitride semiconductor device, a p-type GaN layer, an n-type GaN layer, and a gate electrode are laminated on the barrier layer (Japanese Patent Application Publication No. 2013-80894 (JP 2013-80894 A).
In the nitride semiconductor device according to the above-described related art, the dopant concentration in the p-type GaN layer may be set to be high such that the device is made to be in an off state (normally-off state) in a state where a voltage is not applied to the gate electrode. In addition, the dopant concentration in the n-type GaN layer may be set to be high such that contact resistance with the gate electrode is reduced.